You'll have to depart for the Big Island either this week or next, but waiting til last minute might've just saved you hundreds off the going rate to Hawaii. Flights are available on select dates from JFK through July 20 with returns available through mid-August.
Searching on AA, I found seats departing JFK on Thursday, July 19 and returning from KOA Monday, July 30, 2018.
Flights are also available some departures from LaGuardia, but they will require departures this week. If you can't drop everything and jet off in the next few weeks, then have a look at our New York (JFK) and New York (LGA) flight pages for a list of all our other offerings.
Need a room on the Big Island? Here's what's available for the mentioned dates on Hotelwatchdog.